[Technical x]

Internet Security, Spam Emails and Phishing Messages

Posted by Kevin Maguire on Mar 18, 2015

The Graniterock Information Services team has noticed a recent increase in the problem of spam and phishing emails and phone calls which attempt to steal user information. A Graniterock Team Member recently reported a caller claiming to be from “Microsoft”. The caller told our Team Member his computer had been hacked, but for a fee of $99 Microsoft tech support would remotely repair the computer. This computer was purchased through our Company’s home computer purchase program, so before doing anything he wisely asked us for advice.
Read More

Performance Grade Systems for Asphalt Binders

Posted by Graniterock on Mar 18, 2015

Background
Read More

Willows for Soil Stabilization

Posted by Alex Simons on Mar 18, 2015

With winter comes the cool crisp air and the occasional unexpected erosion problem from heavy rains. Repairing an erosion gully or streambed can seem like a headache, however there is a natural remedy that requires little to no machinery to install: Willows.
Read More

An Overview of Asphalt Sealer Systems

Posted by Graniterock on Mar 18, 2015

Asphalt sealers are not slurry seals (Caltrans section 37.2 specifications) but a lot of people refer to asphalt sealers as slurry seals. Asphalt sealers have been in use for over 40 years and today there are basically three different sealer systems: Asphalt emulsion based sealers, clay emulsion based sealers and coal tar based sealers.
Read More

Hot Mix Asphalt Tennis Courts: Material Selection, Construction, Repair and Maintenance

Posted by Graniterock on Mar 18, 2015

Hot mix asphalt can be used for tennis courts to provide a durable, flat surface with good traction for players, clear defined boundary lines and consistent ball movement. Asphalt surfaces are not susceptible to rain unlike other types of courts and will not require much maintenance. Asphalt can be placed and compacted to develop one level surface without joints and will also allow for specialized coatings to be placed on the surface.
Read More

Warm Mix Asphalt Update

Posted by Graniterock on Mar 18, 2015

Warm Mix Asphalt (WMA) is the name given to conventional Hot-Mix Asphalt (HMA) that is modified by additives or changes in manufacturing processes that allows asphalt mixes to be produced and placed at low temperatures. Reductions of 50 to 100 degrees Fahrenheit have been documented.
Read More

Dumbarton Bridge Seismic Retrofit - A Design and Teamwork Challenge

Posted by Keith Severson on Mar 18, 2015

For over a year Shimmick Construction has been retrofitting the Dumbarton Bridge to make safety improvements and increase the its capacity to handle forces caused by earthquakes. The work included the reconstruction of bridge joints to allow for more movement of bridge segments without damage when an earthquake occurs. The joints are composed of heavily reinforced concrete covered by massive steel plates. The construction challenge for Shimmick and Graniterock, the concrete supplier of choice, was to get concrete to entirely fill the cavity under the steel plates through small holes drilled in the top of the steel plates. This meant the concrete needed to be highly fluid and flow freely to make its way around the dense steel reinforcing under the steel plates. The Caltrans specification also required that the mix not segregate into rocky pockets and sandy/cement pockets so that the strength and durability of the concrete was consistent throughout the joint.
Read More

Permeable Aggregate Systems for Playing Fields

Posted by Graniterock on Mar 18, 2015

It’s no doubt that synthetic athletic fields are becoming more popular. Organizations that decide to install synthetic fields have realized lower maintenance costs and better playability. Using a sophisticated system of drainage channels, filter fabrics and specialized aggregate, a well-designed field draws water quickly from the turf layer allowing year-round play and reliable playability in wet weather. 
Read More

Tender Asphalt Mixes - Causes and Cures

Posted by Graniterock on Mar 18, 2015

A“tender” asphalt mix usually refers to a mix that is difficult to compact. It may have a tendency to shove under the roller wheels and/ or leave longitudinal cracks at the edge of the steel drums. Either a lack of friction between particles or a lack of shear strength in  the mix essentially causes tenderness. Both these problems can be the result of many factors, the most common of which we will discuss. 
Read More

Fog Sealing Older Pavements

Posted by Graniterock on Mar 18, 2015

In its “A Basic Asphalt Emulsion Manual”, the Asphalt Emulsion Manufacturers Association and the Asphalt Institute describe a fog seal as a “light application of slow-setting emulsion sprayed on an existing asphalt surface.” Properly applied and applied at the right time, a fog seal can be a valuable aid in the maintenance of an asphalt pavement. The question is, what is the proper application and when is the right time to use fog seals in a pavement maintenance program?
Read More